The Frisians struggle, for several centuries, against their dominion, until eventually subjugated by Charlemagne.

They even encroach upon the Franks in Belgic Gaul, who are determined not to yield their possessions.

Moreover, the pious Merovingian faineans desire to plant Christianity among the still pagan Frisians.

Dagobert, son of the second Clotaire, advances against them as far as the Weser, takes possession of Utrecht, founds there the first Christian church in Friesland, and establishes a nominal dominion over the whole country.
Yet the feeble Merovingians would have been powerless against rugged Friesland, had not their dynasty already merged in that puissant family of Brabant, which long wielded their power before it assumed their crown.
It was Pepin of Heristal, grandson of the Netherlander, Pepin of Landen, who conquered the Frisian Radbod (A.D.

692), and forced him to exchange his royal for the ducal title.
It was Pepin's bastard, Charles the Hammer, whose tremendous blows completed his father's work.